ConcurrentModificationException - How to get one.

ConcurrentModificationExceptionGenerator.java

public class Map {
  
	public static void main(String[] args) {
		HashMap<Integer,Long> map = new HashMap<Integer,Long>();
		for(int i = 0;i<100;i++){
			map.put(i,System.nanoTime());
		}
		Iterator<Integer> it = map.keySet().iterator();
		while(it.hasNext()){
			map.remove(it.next());
		}
	}
}